Singleton (boo) + Adapter (yay)

singleton.php

<?php

class Singleton {

    public static $aliases = array();

    protected static $_adapters = array();

    public function __construct () {
        throw new LogicException("you cannot instanciate Singleton");
    }

    public static function register ($adapter, array $config = array()) {
        $class = $adapter;

        if (isset(static::$aliases[$adapter]))
            $class = (string)static::$aliases[$adapter];

        if (!class_exists($class, true))
            throw new RuntimeException("no such class $class");

        if (!in_array('SingletonAdapter', class_implements($class)))
            throw new LogicException("$class doesn't implements SingletonAdapter");

        static::$_adapters[$adapter] = compact('class', 'config');
    }

    public static function resolve ($adapter) {
        if (!isset(static::$_adapters[$adapter]))
            return false;

        if (static::$_adapters[$adapter] instanceOf SingletonAdapter)
            return static::$_adapters[$adapter];

        extract(static::$_adapters[$adapter]);
        return static::$_adapters[$adapter] = new $class($config);
    }

    public static function __callStatic ($method, $args = array()) {
        if (!$adapter = static::resolve($method))
            throw new RuntimeException("no such adapter $method");

        return $adapter->invoke($args);
    }
}

interface SingletonAdapter {

    public function __construct (array $config);

    public function invoke (array $args);
}

class CallbackSingletonAdapter implements SingletonAdapter {

    protected $_closure;

    public function __construct (array $config) {
        if (!isset($config['closure']))
            throw new RuntimeException("no closure provided");

        if (!$config['closure'] instanceOf Closure)
            throw new RuntimeException("not a valid closure");

        $this->_closure = $config['closure'];
    }

    public function invoke (array $args) {
        return call_user_func_array($this->_closure, $args);
    }
}

$closure = function ($a, $b, $c) {
    var_dump($a, $b, $c);
};

Singleton::$aliases['a'] = 'CallbackSingletonAdapter';

Singleton::register('a', compact('closure'));
Singleton::a(1,2,3);